Introduction: The objective of this study was to evaluate the efficacy and safety of decitabine in Chinese patients with myelodysplastic syndrome (MDS). Methods: Patients (≥18 years) who had a de novo or secondary MDS diagnosis according to French–American–British classification and an International Prognostic Scoring System score ≥0.5 were enrolled and randomized (1:1) to one of two decitabine regimens: 3-day treatment (3-h intravenous infusion of 15 mg/m2 given every 8 h for three consecutive days/cycle/6 weeks) or 5-day treatment (1-h intravenous infusion of 20 mg/m2 once daily on days 1–5/cycle/4 weeks). After a minimum of 30 patients were assigned to 3-day schedule, the remaining were assigned to the 5-day schedule. The primary efficacy endpoint was the overall response rate (ORR). Secondary outcome measures included hematologic improvement (HI), cytogenetic response rate, the time to acute myeloid leukemia (AML) progression, and overall survival (OS). Results: In total, 132 of 135 enrolled patients (3-day treatment, n = 36; 5-day treatment, n = 99) discontinued treatment (major reasons included patient withdrawal/lack of efficacy, n = 48; adverse events, n = 23; and disease progression, n = 22). During the study, 35 of 132 (26.5%) patients from the intent-to-treat (ITT) group achieved significant (P Source